Anode for cathodic protection system



July 10, 1962 w. T. BRYAN ETAL ANODE FOR CATHODIC PROTECTION SYSTEM Filed Feb. 27, 1958 FIG FIG-1 a O 9N 66 7l wvo INVENTORS WILLIAM T BRYAN a BY JOHN L. ARWINE MMM/1662?? ATTORNEYS FIG-5 lar United States This invention relates to cathodic protection systems for combating and inhibiting corrosions in metallic structures subjected to electrolytic corrosive action in the surrounding medium in which they are installed and, more particularly, to anode structures for such cathodic protection systems.

Structures such as metal pipe lines, underground cables and conduits, metal tanks and steam pipes, metal piers, etc., may be subjected to substantial and expensive electrolytic corrosion as installed beneath the surface of the ground, in sea water, `under streams, and/or otherwise in contact with an electrolytic medium or environment. Such corrosive action may result fromk electrolytic cell action through the surrounding medium in which the metallic structure becomes anodic with respect to another object or another part of the same structure so that metal in the structure is actually electrochemically removed from those portions of the structure which are lanodic with respect to another element of the electrolytic cell, and, since such anodic areas are frequently small by comparison to the cathodic object or area, a high current density may result at the anode causing rapid failure of the structure.

One method of combatting such corrision is to provide adjacent the corrosive structure a so-called cathodic protection system in which an anode is provided in electrolytic cell relation with the structure to be protected and a suitable electric current is impressed to maintain the anode anodic with respect to the structure to be protected thereby avoiding electrochemical removal of material from the structure. Such a cathodic protection system and apparatus therefor is described in the application of Walter A. Luce and Marselio G. Fontana, Serial No. 440,448 tiled June 30, 1954 now abandoned, and the continuation-in-part copending application thereof, Serial No. 667,808, led June 25, 1957, now abandoned, in which the use of a high silicon iron casting is disclosed for the protecting anode as providing increased anode life and enhanced electrolytic and electrochemical characteristics for impressed current cathodic protection systems.

Esecially with the cathodic protection of extended subterranean pipe lines and electrical cables, as well as with large-metal piers, and the like, it is desired that the cathodic protection `system itself have as long a life as possible to reduce maintenance problems, etc. In such systems, of course, the action of the impressed current in the cathodic protection of a metal structure may accelerate or enhance the possibility of corrosive destruction of the .protecting anode and its appurtenant wiring. It has been found,.particularly, that the point of connection of the wiring leads to the protecting anode are especially subjected to electrolytic corrosion, as Well as are such fweak links in the protection and as points of juncture of two anodes, etc.

It has also been discovered that optimum electrochemical characteristics of either anode materials or interconnecting wiring may be inconsistent with the mechanical strength and/ or electroconductive characteristics of various materials. p For example, a specific high silicon iron of desired electrochemical and anticorrosion characteristics for an anode may have such high brittleness, lack of machine ability, and poor tensile or impact strength as to be, alone impractical to withstand or conform to the physical requirements of some installations arent Q l *3,043,765` Patented July 10, 1962 ICC and/or metallurgically ill-suited to electrical connection with a lead wire in a manner which will protect the point of connection from excessive corrosion and failure in a shorter `time than the expected and desired anode life.

With such high silicon iron anodes, some diiculty may -be experienced in the manufacture thereof if it is attempted to incorporate into the anode body an insert or other connecting piece of a metal which may be ma-v chinable or susceptible to a soldered lead wire connection. For example, attempting to incorporate directly such an insert as the high silicon wire casting is made may lead to diiculties in positioning the insert precisely into the mold cavity to be cast into the anode.

Similarly, providing an accurately dimensioned cored recess in the anode body Afor the later insertion of a connection device may well increase the practical difficulty in producing the cast anodes on a commercial scale.

According to this invention, however, structures are provided for the electrical and mechanical connection of the anodes in a cathodic protection system to provide both electrical and chemical insulation of the electric connection against corrosion, etc., as Well as increased mechanical strength at the point of connection as required, and structures `according to this invention are also advantageously susceptible to mass producing the anode castings in and with standardized electrical connection means yet without the necessity for accurately cored portions of the casting and Without the necessity of using separate inserted connecting members for the lead wire yet with the provision of means for the utilization of an interlocking machinable insert in the standardized production device should this expedient be desirable.

One object of this invention is to provide, in an elecf trode of the character described, a protective electrical connection for connecting the electrode to a lead wire and protecting the connection from corrosion attack, all in the labsence of the use `of a separate connecting element or insert yet while providing an interlocking connection having mechanical or tensile strength suicient lto maintain the lead wire connected to the anode under tensile conditions as may be encountered in use which tend to pull the lead wire out of or away from connection with the anode.

Another object of this invention is to provide, in an' electrode of the character described, a standardized connecting structure either for mechanically joining one electrode to another utilizing a machinable connecting device inserted into the electrode or for making Van adequately strong electrical and mechanical connection inthe absence of a separate insert between the electrode and 'a lead wire therefor. s

A further object of this invention is to provide, in an electrode of the character described and formed of a material unsuited for machined or welded or soldered mechanical or elemental connections to a wire or a separate connecting element, or means for the interlocking mechanical and electrical connection of a lead wire to the electrodewithout a separate-connecting structure, which means will withstand the disruptive tensile forces to which such connection is subjected in use, and including provision for insulating said connection both electrically and mechanically within the electrode to protect the connection from corrosive contact with fluid media in which the electrode and the connection are subjected in use. Still another object of this invention is to provide, in electrodes of the character described, connecting means for interconnecting a plurality of electrodes with each other and/or with one or more klead Wires to produce an electro-conductive juncture which will withstand the tensile and other mechanical disruptive forces to which it is subjected in use and yet which is provided without the necessity of separate connecting devices.

A still further object of this invention is to provide, in electrodes of the character described, connecting means for interconnecting a plurality of electrodes with each other and/ or with one or more lead wires to produce an electroconductive juncture which will withstand the tensile and other mechanical disruptive forces to which it is subjected in use and yet which is accomplished by a standardized connecting structure cast into the electrode body for use both in the case where a lead wire is connected to the electrodes and in the case where the electrodes are mechanically rigidly connected together by an interposed rigid connecting element.

Other objects and advantages of this invention will be apparent fromthe following description, the accompanying drawing, and the appended claims.

In the drawing,

FIG. l is a view partially in longitudinal section through a connection ofthe lead Wire to an electrode embodying this invention;

FIG. 2 is a plan view of a plurality of electrodes connected together 4by lead Wires for a cathodic protection system embodying this invention;

FIG. 3 is a view similar to FIG. 1 illustrating a modiiication of a lead wire connection and insulating structure embodying this invention;

FIG. 4 is a view in longitudinal section of a further form of electrode embodying this invention and adapted to be connected to a lead wire intermediate the extreme ends thereof;

FIG. 5 is a somewhat diagrammatic view of the electrodes of FIG. 4 connected to a lead wire at various points therealong;

FIG. 6 is a detailed fragmentary view on an enlarged scale of a plastic compression closure washer as part of the electrical and chemical insulating means of structures embodying this invention `and as shown in FIGS. 1, 3, and 4;

FIG. 7 is a fragmentary longitudinal section of a connection structure embodying this invention and adapted to connect a pluralityrof anodes rigidly together; and

FIG. 8 is a view in elevation partly broken away of a form of electrode embodying this invention and including in one end thereof the rigid connection of FIG. 7.

Referringto the drawing, in which like reference characters refer to like parts throughout the several views thereof, the end portion of an anode 10 is illustrated in FIG., l as applied particularly to a cast iron anode of generally elongated cylindrical shape and having a high silicon content (for example, of the order of 12% to 15% silicon in the cast iron) and sufficiently high to render the cast iron anode 10 too hard or brittle to be susceptible to machining and/or soldering or welding operations. Anode 10 is illustrated as having an enlarged end portion 11 and a recess 12 of generally cylindrical configuration formed in the enlarged end. portion 11. vRecess 12 is satisfactorily formed by being cast into anode 10 during the process of manufacture of the anode, as, for example, by having a sand core of the desired shape in the mold in known manner.

The innermost portion 13 of recess 11 is formed as an undercut or otherwise in a manner so that a fusible material poured thereinto to fill completely portion 13 of recess 12 will, upon solidiiication, positively interlock against withdrawal therefrom. As illustrated in FIG. 1, this interlocking inner portion 13 of recess 12 may satisfactorily be formed in a frusto-conical configuration. Satisfactory results are also obtained, according to this invention, as illustrated in FIG. 3 where a generally cylindrical anode 1S is provided with an enlarged end portion 16 in which there is a cored recess 17 of generally cylindrical configuration having an innermost portion 18 for the aforementioned interlocking of a fusible material therein but with the portion 18 being formed in a generally spherical configuration ratherthan the f rustro- 4 conical configuration of portion 13 of recess 12 illustrated in FIG. 1.

As will be understood, `anodes embodying this invention may be immersed in sea water or fresh water (as in a water tank or standpipc) or immersed or embedded in damp soil or a so-called backtill adjacent to the structure which it is desired to protect by the cathodic protection system embodying electrodes according to this invention. Since anodes of this invention are particularly adapted for use in so-called impressed current cathodic protection systems, it is required that a lead wire or other insulated electrical connector be electrically and mechanically connected to the anode. As is well understood, such electrical connectors may be formed of a material different from the anode material itself, most frequently copper wire, and, because of the electro-chemical difference between the copper of the lead wire andthe anode material, among other reasons, the connection of the lead wire to the anode forms what might be described as the weakest link of the chain in terms of the susceptibility of the entire system to the electrochemical corrosion. Thus, if the connection between the copper lead wire and the high silicon iron anode is accessible to the electrolytic surrounding medium in which the anode is disposed, corrosion of this connection and of the yanode -at this connection will be accelerated to a point where failure of the entire system may well result long before the useful life of the anode itself is expended.

Furthermore, in such cathodic protection systems, the anode itself may be mechanically suspended or supported from the lead wire and/ or the anode may be installed or pulled into its operative position (for example, through a conduit or duct in which cables or pipes which it is desired to be protected are disposed) so that, in addition to a rrn electrical connection, a strong mechanical connection between the lead Wire and the anode is advantageous. Similarly, such connection should be both electrically and, as noted, chemically insulated from the surrounding medium.

Such features and advantages are provided by this invention, as illustrated in FIG. 1, for example, by recess 12 with the interlocking portion 13 being cast into the anode 1li. The connection between anode 10 and a lead wire 20 is formed by ybaring the end 21 of the lead wire 2t) from the electrical insulating layer 22 therearound as indicated and inserting the bared end 21 of the lead wire 20 into the undercut portion 13 of recess 12 in the end 11 of anode 10. With lead wire 20 so positioned, lead or some other readily fusible material having appropriate electroconductive characteristics is melted and poured into recess 12 around lead Wire 20 so that, when the lead solidifies upon cooling, a lead plug 25 will be formed in undercut portion 13 of recess 12 solidly uniting lead wire 20 with anode 10 for the electrical circuit, and, because of the undercut or frustro-conical or dove-tail configuration of portion 13 of recess 12, the solidified lead plug 25 will also anchor or atiix wire 20 mechanically solidly into the recess 12. As will be understood the bared end 21 of lead wire 20 is preferably tinned prior to the introduction of lead into the recess, and, as will also be understood, such materials as babbit metal, solder, and other similar low-melting alloys may be utilized satisfactorily to form a fir-m and strong electrical and mechanical connection between lead wire 2t! and anode 10 entirely within the anode in recess 12 and removed from the outer or exposed end of anode 10.

Also, as indicated in FIG. 3, a similar connection is formed in the recess of the illustrated embodiment with the provision of a solid plug 26 of lead or other readily fusible metal filling the spherical portion 18 of recess 17 to unite the bared end 21 of lead wire 20 both mechanically and electrically with the main body of anode 15.

After lead Wire 20 is so leaded in place, the remaining portion of recess 12 or 17 is preferably lled with a nonsolidifying insulating plastic mastic, as indicated at 30 to protect and insulate electrically and chemically the leaded connection of lead wire 2o withlead plug 25 or 26 and anode or 15. One satisfactory material for the plastic insulating mass 30 is Ozite, an asphalt base caulking compound.

After introduction of mastic 3i) into the recess 12 or 17, a firm and water-tight closure of the recess is made by the insertion thereinto of one or more plastic compression Washers 32 which lit into the recess and around the electrical insulating layer 22 of lead wire 20. Preferably such washers 32 have an outside diameter just larger than the diameter of recess 12 for a forced tit thereinto compressing the plastic material of washers 32. As indicated more particularly in FIG. 6, the `outer surfaces of washers 32 may advantageously be tapered to enhance the compression effect, and, also as noted in FIG. 6, the inside surface of washers 32 preferably include one or more compression rings 33 provided so that, when washers 32 are fitted around the outer insulating layer 22 of lead wire 2@ and compressed into recess 12 or 17 in the anode, compression rings 33 will embed themselves into the outer plastic insulating coating `22 of lead wire Ztl to enhance the water-tight nature of the closure of the outer end of recess 12 or 17.

As noted in FIG. 3, and as particularly adapted for submersion in sea water for extended periods as, for

example, to protect cathodically sea water installations such as metal piers and the like, a further protective closure may be provided over the end of the `anode as by, for example, a plastic cap 35 applied `over and around compression washers 32 and lead wire 2t). In such situations, a further undercut `or dove-tail recess 36 may be advantageously cast into the outer end 16 of anode 15 to provide a positive mechanical anchor for the plastic cap 35. Satisfactory results are obtained if compression washers32 are formed of polyethylene plastic and, in instances when the outer plastic cap 35 is utilized, a satisfactory material for'the formation thereof is epoxy resin. As will be understood, the foregoing arrangement of lead wire connection in'to `an anode constructed to embody 'or yfor practicing this invention may be either the connection of a lead wire from yone end only of the anode or, indeed, may be the type of connection illustrated in FIG. 2 in which a plurality of anodes are connected together with lead wires in between. Even with such connections and the lead wires in between, still one can produce anodes with the standardized recess 12 or 17 and with the undercut portion 13 or ,1S for any particular lead wire `connection as may be desirable.

` As a further embodiment of an anode according to this invention and particularly adapted to having a plurality of such anodes strung on a wire to be pulled through a conduit or other type of arrangement whereby a long 'cable is desired to be cathodically protected, the type of anode of FIG. 4, -may be advantageously provided. In this arrangement there is provided an anode body 46 of the same high silicon content as Withthe anodes 10 or 15. Anode 4'() is cast in the general form of a cylindrical piece of pipe, with, however, certain particular arrangements `inaccordan'ce with this invention. Anode 40 is provided in an essentially elongated cylindrical shape with the inside thereof being essentially hollow, with chamfered Vedges being preferably provided at 41. An indent 42 is provided generally midway between the ends of anode 4G, `as also is an annular abutment or indent 43 for purposes hereinafter to be disclosed.

With the generally cylindrical form of anode 40 and including its high silicon content and protuberances 42,

las well as annular protuberances y43 longitudinally spaced sheaves tration, that portion of lead wire 20 designated in the drawings as a lead wire 20a, and, preferably, the hole in the inside of washer 45 is of such diameter as will accommodate lead wire 20 and its layer of insulation 22 thereon. Washer 45 is, as will be understood, of a diameter suiciently large to transcend the annular opening eft by the annulus 43 cast into anode 40.

In this way, washer 45 is placed over the bared end of one lead wire, for example, 26a, and this lead wire, with the washer 45 thereon, is inserted into one end of anode 4i). With this lead wire 20a and the washer 45 thereon in place, inside of anode 40 and with the washer 45 bearing against annular protuberance 43, another end of a lead wire 20, bared at 21 of its insulating material 22, is inserted from the opposite end of anode 40. With both lead wires in place, -a quantity of lead or solder or babbit metal or other fusible material is poured in from the left end of anode 40 to form, upon cooling, a solid plug uniting the bared ends 21 of the two leads, which are preferably previously tinned, to anode 40. As will be understood, of course, the projection 42 aids in the mechanical anchoring and maintenance of the two lead wires 20 and Zita in the anode 4u through the help of the lead or babbit metal or solder plug, In the foregoing operations, as will be understood, washer 45, interfitting with the annulus 43 cast or cored into the internal diameter of Ianode 40, forms an abutment against which the lead or other readily fusible material can be poured from the left end of anode 4t) (as viewed in FIG. 4) to form the solid block 5@ uniting the various lead wires in anode 40'.

After the leaded joint is formed in anode 40 to unite mechanically, and as well as electrically, the lead Wires therein the remainder of anode 40 is lled with plastic mastic, as with the interior of recesses 12 or 17, about a lead wire connection thereinto. After the interposition of a mastic mass 55, compression washers 32 are intertted into the anode 40, as such washers are iuterfitted into the outer end recesses 12 or 17, it being understood that a variance of diameter may, indeed, be achieved but, the compression washers are, essentially the same as those washers 32 for intertting into the outer end recesses 12 or 17, and including the compression rings 33` which bite or otherwise impress themselves into the outer circumference or surface of the plastic insulating layer 22 around electrical conductors 20 and 20a, as indicated at 34, in much the same way as is achieved in FIGS. 1, 3, and 6.

Since anode 46-or the entire structure as diagrammatically illustrated in FIG. 4is primarily adapted for pulling through a conduit or other constricted space, the ends of anode 4t) outwardly of the compression Washers 32 are closed by a generally conical cap 55 which may, satisfactorily be of polyethylene plastic and which may satisfactorily interfit, as indicated in FIG. 4, with the end portions of anode 40 as well as with and around the insulating layer 22 of lead wire 20. It should be noted, however, that the electrical and chemical and electrochemical insulation of the joint within anode 40 is, by and large, accomplished by the plastic mastic mass 55 and compression washers 32, rather than by the plastic cap 56 which, indeed, is, because of its conical shape, rather more a mechanical guide for pulling anode 40 through whatever conduits or ducts in which it may be disposed than any electrochemical or electric insulating means. In

this connection it should be noted that slant or slope of conical cap 55 is, preferably, correlated with the chamfered surface41 on the ends of anode 40.

As illustrated in FIG. 5, a plurality of anodes 40 are illustrated as being strung upon or interconnected with, according to this invention, an elongated lead wire 20 to provide, as heretofore discussed, the cathodic protection anode structure which may be pulled through a conduit or duct or other arrangement to include the various benetits and advantages of an anode constructed for incorporation into the lead wire 20 intermediate` the ends thereof, as illustrated diagrammatically in FIG. 4.

In some installations, such as, for example, the cathodic protection of tall standpipes or water tanks, it may be desired to connect a plurality of anodes or anode segments rigidly together to form one long anode. A satisfactory structure embodying this invention for accomplishing such rigid connection is illustrated in FIG. 7 as having a recess 12 with an undercut or interlocking portion 13 cast into the end of an anode 65. An insert connector 66 is provided of a metal which is readily machineable, and is formed having a diameter somewhat less than the smallest diameter of recess 12 with at least one interlocking protuberance or projection such as 67 or other irregular exterior surface. In this illustrated embodiment, the outer end of insert 66 has a tapped bore 68 therein.

In assembling the connection, insert 66 is inserted into recess 12 and lead or solder or babbit metal or other readily fusible metal is poured into the recess surrounding and enveloping insert 66 to form upon cooling and solidiication a solid plug 69 which rigidly interlocks and maintains insert 66 in recess 12. With such structure, then, a threaded lug 70, preferably provided with a plastic insulating washer 71, unites two such anodes or anode segments 65 by screwing them together end to end with lug 70 en- -gaged in tapped bore 68 in inserts 66, and, upon screwing two such segments tightly together, washer 71 is compressed therebetween to form an insulating closure for each of the recesses 12 in each such anode segments as illustrated in FIG. 8. 'In this way, any number of anode segments 65 can be screwed together in end-to-end relation to forma composite anode of the length desired. As indicated in FIG. 8, the end anode segment of such a composite arrangement has a lead wire 20 afrixed into the recess 12 therein as, for example, by the connection shown in FIG. 1.

According to this invention, then, structures are provided for connecting lead wires or rigid connectors into electrodes of the character described notwithstanding the fact that such electrodes may be made of a material which cannot satisfactorily or readily be machined or welded r soldered, 'and means are also provided for insulating `such connections both electrically and chemically from contact with the surrounding medium in which the anode and the connection may be placed. Furthermore, considering the various types of anodes to which connection is to be made, the forms and structures embodying this invention provide for producing standardized anodes with a standard recess readily cast into the end thereof so that a single form of recess can be used Whether it is subsequently desired to connect the lead wire to the anode as 4in FIG. l or a rigid connector as in FIG. 7. Because of the interlocking nature of the lead plugs 25, 26, 50, and 69 in the undercut or protruding portions 13, 18, `and 42 of the various recesses for the insertion of bared ends 21 of the lead wires or irregularly shaped inserts 66 thereinto, a mechanical juncture is formed of adequate Inechanical strength to withstand any pulling or tensile forces t-o which the anodes may be subjected in use, it being understood that, in actual practice, the bared ends 21 of lead wires 20 may be curved or askew or irregular positioned within the various recesses rather than being symmetrically positioned therein as shown in the drawings for illustrative purposes.

While the forms of apparatus herein described co-nstitute preferred embodiments of the invention, itis to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made -therein without departing from the scope `of the invention which is dened in the appended claims.

What is claimed is:

1. An anode construction for a cathodic protection system of the character described having a plurality of anodes connected in spaced relation along a lead wire with said connections having sufficient mechanical strength Vfor said lead wire with said anodes connected therealong to be pulled through a conduit and the like as rea for the cathodic protection of structures adjacent said conduit, comprising in combination a generally cylindrical hollow main anode body, an annular constriction within said anode body intermediate the ends thereof for interlocking engagement with a fusible plug therein, a pair of lead wire segments inserted into opposite ends of said anode body into juxtaposition adjacent said constriction, a fusible plug in said anode body and formed of a metal lower melting than said anode body and mechanically and electrically connecting both said lead wire segments with said anode body through said constriction therein forming an electrical connection therebetween and a mechanical connection resistan-t to longitudinal tensile forces tending to separate either of said lead wire segments from said body, plastic insulating means around said wires and said connections and outwardly spaced there'- from longitudinally of said anode body forming a watertight closure electrically and chemically insulating said connection of said lead wire segments to said anode body and said fusible plug from a surrounding medium in which said anode may be disposed,

2. An anode construction for a cathodic protection system of the character described having a plurality of anodes connected in spaced relation along a lead wire with said connections having sufcient mechanical lstrength for said lead wire with said 'anodes connected therealong to be pulled through a conduit and the like for the cathodic protection of structures adjacent said conduit, comprising in combination a generally cylindrical hollow main anode body, an annular constriction within said anode body intermediate the ends thereof for interlocking engagement with a fusible plug therein, a pair of lead wire segments inserted into opposite ends of said anode body into juxtaposition adjacent said constriction, a fusible plug in said anode body and formed of a metal lower melting than said anode body and mechanically and electrically connecting both said lead wire segments with said anode body through said constriction therein forming an electr-ical connection therebetween and a me chanical connection resistant to longitudinal tensile forces tending to separate either of said lead wire segments from said body, an annular inward projection in said lanode -body and spaced from said constriction, `assembly washer means on one of said lead wire segments for interitting a closure with said annular projection forming a limiting mold for the formation of said fusible plug within said anode, plastic insulating means around said wires and said connections and outwardly spaced therefrom longitudinally of said anode body forming a watertight closure electrically and chemical insulating said connection of said lead wire segments to said anode body and said fusible plug from a surrounding medium in which said anode may be disposed.

3. An anode construction for a cathodic protection system of the character described having a plurality of anodes connected in spaced relation along a lead wire with said connections having sufficient mechanical strength for said lead wire with said anodes connected therealong to be pulled through a conduit and the like for the cathodic protection of structures adjacent said conduit, comprising in combination a generally cylindrical hollow main anode body, an annular constriction within said anode body intermediate the ends thereof for interlocking engagement with a fusible plug therein, ya pair of lead wire segments inserted into opposite ends of Said lanode body into juxtaposition adjacent said constriction, a fusible plug in said anode body and formed of a metal lower melting than said anode body `and mechanically and electrically connecting both said lead wire segments with said anode body through said constriction therein forming an electrical connection therebetween and a mechanical connection resistant to longitudinal tensile forces tending to separate either of said lead wire segments from said body, and endclosure means forming a watertight joint around said lead wire segments electrically and chemically insulating said connection from Ia surrounding medium in which said anode is disposed and forming beveled guide means facilitating pulling said anode through said conduit.

4. An anode construction for a cathodic system of the character described, comprising in combination a metal anode body portion, an elongated axial recess cast into an end of said anode body portion, an electricalconductor leading out of said recess for providing electrical and mechanical connection of said anode into said cathodic protection system, a transverse constriction in said recess and spaced from both inner and outer ends thereof for aiding in mechanically connecting said conductor to said anode body portion, said recess having outwardly of said constriction a substantially uniform cross-section substantially larger than the transverse dimension of said electrical conductor, a fusible plug of a metal lower melting than said metal anode body and formed in said recess interlocked therein with said constriction and engaging and electrically and mechanically connecting said conductor to said anode body portion in said recess, and plastic closure and insulating means closing the outer end of said recess around said electrical conductor effecting a watertight closure of said recess for electrically and chemically insulating said connection of said conductor to said anode in said recess.

5. An anode construction as recited in claim 4 in which said metal anode body portion is formed of high silicon 8. An anode construction as recited in claim 6 in which said plastic closure and insulating means includes a mass of plastic insulating material packed into said recess around said wire and outwardly of said constriction and said fusible plug engaging said wire in said recess.

9. An anode construction as recited in claim 8 which also includes a plastic washer closing the outer end of said recess around said Wire lfor retaining said mass of insulating material packed in said recess.

10. An anode construction as recited in claim 4in which said plastic insulating and closure means includes a plastic cap covering substantially the entire end surface of said anode body portion around said conductor.

11. An anode construction as recited in claim 10 in which said anode body portion includes means cast thereinto adjacent the outer end of said recess for anchoring said plastic cap thereto.

12. An anode construction as recited in claim 4in which said mechanical and electrical connection between said conductor and said anode body also includes a machinable insert of `a metal different from both said anode body and said lower melting fusible plug, said insert being substantially smaller than said recess and being interlocked in said recess by said fusible plug and said constriction, and means in said insert for connecting said conductor thereto.

13. An anode construction as recited in claim l2 in which said insert includes projecting surfaces for irrn interlocking engagement with said Ifusible plug in said recess and cooperating with said constriction therein for interlocking rmly into said recess.

References Cited in the file of this patent UNITED STATES PATENTS 1,489,743 Delius et al. Apr. 8, 1924 1,788,485 Gunderson Jan. 13, 1931 2,803,602, Cowsky et al Aug. 20, 1957 2,808,373 'Andrus Oct. 1, 1957 2,876,190 Oliver Mar. 3, 1959 

4. AN ANODE CONSTRUCTION FOR A CATHODIC SYSTEM OF THE CHARACTER DESCRIBED, COMPRISING IN COMBINATION A METAL ANODE BODY PORTION, AN ELONGATED EXIAL RECESS CAST INTO AN END OF SAID ANODE BODY PORTION, AN ELECTRICAL CONDUCTOR LEADING OUT OF SAID RECESS FOR PROVIDING ELECTRICAL AND MECHANICAL CONNECTION OF SAID ANODE INTO SAID CATHODIC PROTECTION SYSTEM, A TRANSVERSE CONSTRICTION IN SAID RECESS AND SPACED FROM BOTH INNER AND OUTER ENDS THEREOF FOR AIDING IN MECHANICALLY CONNECTING SAID CONDUCTOR TO SAID ANODE BODY PORTION, SAID RECESS HAVING OUTWARDLY OF SAID CONSTRICTION A SUBSTANTIALLY UNIFORM CROSS-SECTION SUBSTANTIALLY LARGER THAN THE TRANSVERSE DIMENSION OF SAID ELECTRICAL CONDUCTOR, A FUSIBLE PLUG OF A METAL LOWER MELTING THAN SAID METAL ANODE BODY AND FORMED IN SAID RECESS INTERLOCKED THEREIN WITH SAID CONSTRICTION AND ENGAGING AND ELECTRICALLY AND MECHANICALLY CONNECTING SAID CONDUCTOR TO SAID ANODE BODY PORTION IN SAID RECESS, AND PLASTIC CLOSURE AND INSULATING MEANS CLOSING THE OUTER END OF SAID RECESS AROUND SAID ELECTRICAL CONDUCTOR EFFECTING A WATERTIGHT CLOSURE OF SAID RECESS FOR ELECTRICALLY AND CHEMICALLY INSULATING SAID CONNECTION OF SAID CONDUCTOR TO SAID ANODE IN SAID RECESS. 